Over the last few decades, the Mekong River basin’s riverine ecosystems, which contain the world’s largest inland fishery, have experienced a number of critical changes, particularly due to the development of a large number of hydropower dams upstream. Many of these projects have caused serious social and environmental impacts, ones with implications far beyond the locations where the projects were constructed.

The Mekong River, well known for its aquatic biodiversity, is important to the social, physical, and economic health of millions living in China, Myanmar, Laos, Thailand, Cambodia, and Vietnam.

China’s irresponsibility and inconsideration towards other Mekong countries

Despite the fact that the Mekong is a shared resource flowing through several Southeast Asian countries before emptying into the South China Sea, China considers water originating within its borders to be sovereign property, rather than a resource to be shared with downstream countries.

This is not surprising, as China has a long history of non-cooperation in the Mekong Basin, at least when it comes to discussing its own plans for dam-building on the Mekong. Downstream impacts are rarely considered, and never sufficiently. Within China itself, the lack of transparency and collaboration with local actors is also concerning.

The fact that no consensus among Mekong River Commission members, made up of those in the lower Mekong basin, needs to be reached for a dam to be planned, approved, or constructed, means that governments can prioritize their economic benefits at the expense of others.

The lack of communication has led to several trans-boundary disputes between the public-private dam builders and the people and governments who are downstream from the hydropower dams and most likely to be affected by their construction.

China’s progress without considering other Mekong counterparts has led to downstream countries such as Laos to see no reason on why they should hold back on developments on the shared river when the upstream country is already doing so.  Poor governmental decisions may cause further impacts to the villagers and ecosystem.

Likewise, in the case of the Yali Falls Dam, Vietnam’s unwillingness to equitably consider downstream impacts in Cambodia, along with Cambodia’s weak financial and technical capacity, led to a deficient environmental impact assessment that only considered possible impacts 6 km downstream.

The changing ecosystem

The Lancang dams in the upper Mekong within China have caused extreme changes to water level downstream. There are disruptions to river hydrology, unseasonable and sudden releases or constraint of flow, and accentuation of periods of low precipitation, run-off, and drought.  These disruptions have led to multiple serious impacts for communities in the Golden Triangle area of Laos and Thailand.

The above problems have cascading effects such as riverbank erosions; loss of homes and riverbank farms; loss of access to water for drinking and agriculture; loss of harvest of aquatic resources including fish, shrimp, and edible algae; and disruption of fish migration and spawning triggers, reportedly leading to declines in fish populations.

Villagers are suffering

NGO Forum on Cambodia’s research on Mekong dams has provided significant evidence of social problems like food security and uncertainty of livelihoods of millions of people. For example, unexpected strong water releases from the dams led to boats capsizing, as well as the loss of life and property, including fishing gear and boats.

As many riverine communities downstream rely on fishing for food and income, these losses threatened food security and incomes. Important fish habitats, such as deep-water pools, have been silted up, and water quality has changed. Fish populations have subsequently been seriously impacted.

The inability to farm or fish, has forced locals to the extremes.  Some villagers, out of frustration and desperation, have even turned to stealing from the construction site to try to make ends meet while others move to urban areas for low-paying and notoriously difficult construction work in order to support their families.

Health hazard

The construction of hydropower dams have posed challenges to locals. The poor water quality released from the dam is associated with health problems including death. In the construction of the Yali Falls Dam, villagers downstream in Cambodia complained of stomach infections, eye irritations, and rashes, among other ailments. Children who spent time in the river bathing and swimming were more susceptible to illness.

In 2009, toxic blue-green algae were found in the Yali Falls Dam’s reservoir in Vietnam, which was believed to have caused illness and death of people, domestic and wild animals. Changes to the river have been meet with fear and uncertainty. Some families even moved inland to forested areas or agricultural lands, creating other types of land-based environmental impacts.

The relocation of villagers for the construction of dams also posed a problem.  While some villagers insisted on remaining near their former villages and relocated to higher ground, others reluctantly agreed to resettlement packages. But all of them continued to worry about loss of agricultural and forest lands, lands for grazing, and the long distances they now lived away from water bodies.

The suitability of resettlement sites was also a problem. Deforestation rates have been on the rise, making certain locations unliveable. Without land to cultivate and with less fish to catch, villagers have been left without alternative livelihood options.

In the case of the Pak Min Dam, completed in 1994, some villagers were unexpectedly resettled in flood zones, leading to new concerns for the safety of their lives and cattle. The fact that villagers were not given compensation and were relocated to problematic areas, worsened their situation.

Dwindling number of fishing communities

Without enough fish, along with other societal changes, younger generations have stopped fishing and turned to other means to support their families. This has led to a loss of knowledge transmission. Knowledge about fishing gears and the harvesting of aquatic resources has been lost, as there are fewer people to carry on livelihoods associated with the river, resulting in the loss of important elements of local culture and identity. In many villages, only the elderly and young children remain.

The lack of a clear governmental resettlement policy or associated legislation on resettlement and compensation remains a deficiency of hydropower development schemes. The loss of fisheries needs to be more seriously addressed, especially in areas upstream, where migratory fish species no longer reach in the same numbers, thus negatively impacting the food security and incomes of local people.

Photo credit: iStock/Manos Fikaris